Precipitation and nitrogen (N) fertilization are the two important drivers for soil nitrous oxide (N2O) emission. However, the effects of N fertilization and precipitation pattern changes (i.e. precipitation intensity and frequency) on N2O emission in agricultural fields are still unclear. In this study, we simulated soil N2O emission under different precipitation patterns (6 precipitation intensities, and 12 precipitation frequency changes by either merging or splitting precipitation events without changing precipitation intensity), N fertilization rates (low, typical, and high N fertilization), and their interactive effects in a cornfield using the DeNitrification-DeComposition (DNDC) model. The model has been parameterized and validated in previous studies and the base meteorological data and N fertilization data for model simulations were collected in Nashville, Tennessee, USA.
Results/Conclusions
Simulated soil N2O emission increased with increases in precipitation intensity and decreased as precipitation intensity decreased. Less frequent but high intensity precipitation greatly simulated soil N2O emission, particularly in the high N fertilization rates. Compared to the typical N fertilization, low N fertilization decreased soil N2O emission by 43.7%, while high N fertilization treatment increased N2O emission by 50.6%. The effect of precipitation patterns and their interactive effect with N fertilization on N2O emission could not be explained by a simple linear relationship. We found a distinct asymmetric response of N2O emission to precipitation intensity and the interactive effect with N fertilization. These results provided constructive and valuable suggestion for irrigation and N fertilizer management in agriculture to maintain the biomass production and mitigate the N2O emission.